. >> reporter: the alternative is to rely on nasa which he says only spots about a thousand asteroids a year that may hit earth when there are actually a million out there. but with the sentinel -- >> you can spot a charcoal against the black sky with sentinel from a distance of ten times as far from los angeles to new york. >> reporter: lou says it's not a matter of if, but when, even a small asteroid can cause massive destruction. these pictures from 1908 in tonguska, russia, are proof. and lou successfully completed two space shuttle missions. he says without this type of project, and we are simply flying blind along with all other countries in the world. he says we really need this type of telescope to give us that warning we need to stop the course of any collision with the world. reporting live, in menlo park, marianne favro, nbc bay area news. >> thank you. >>> it's all up to mother nature now. the big time maverick surf contest is almost here. the contest window opens on friday. you know how this works. competitors can be given as little as 24 hours notice. it can only take pl